 To build the kinds of roadways we need in our state, we have to carefully design and construct layers of different materials to form strong, stable, and durable pavements. Typically, the top layers of our roadways consist of asphalt concrete or Portland cement concrete constructed over aggregate base courses. We refer to the construction of these aggregate courses as surfacing placement. The same basic methods are used in placing gravel base, ballast, and crushed surfacing for both new and existing construction. An alternate type of surfacing is asphalt treated base, or ATB. But its construction is more like asphalt paving. So it's covered in another training course. The inspection of surfacing placement is necessary to ensure that acceptable material is used. That is, the right type of aggregate, having the proper gradation and quality. The inspection is also necessary to verify that the subgrade is acceptable before the surfacing is placed on it, and that the surfacing is then placed to the correct lines, grades, and cross sections. Testing is part of your inspection, too. It's needed to verify that the required depths and densities are achieved in the surfacing. Documentation and communication are other integral parts of inspection. No doubt about it, surfacing placement does demand your attention. If the surfacing isn't constructed properly, the whole roadway will suffer. As I said a minute ago, acceptable material is of prime concern. The requirements for the different aggregates used in gravel bases, ballasting, and crushed surfacing are in Division 9 of the standard specifications and in Chapter 9 of the construction manual. Stated briefly, the aggregates for gravel bases consist of screened for naturally occurring gravel. Aggregates for ballast consist of crushed, partially crushed, for naturally occurring granular material. And aggregates for crushed surfacing must be manufactured from ledge rock, talus, or gravel. Now let's look at your preliminary inspection concerns, starting with the aggregate sources. At the beginning of each project, a request for approval of material sources must be submitted by the contractor for all materials. Before any aggregate is used on the job, approval of its source must be obtained from the headquarters materials lab. You need to be sure that source approval has been given and that a copy of the form is on file at the project office. In addition, if the source of aggregate changes during the job, see to it that the contractor submits a new request for approval and that the new source is approved before any material from the new source is used on the project. Since the point of acceptance for the aggregate is either as it's placed in the stockpile or as it's loaded into haul trucks, you should go to the pit or quarry and check the setup. If the aggregate to be used is already stockpiled, visually inspected to see if there's any contamination or other problems. And since the aggregate has to meet gradation and quality specifications before it's used, be sure that the required field tests are conducted as soon as possible. Next, make sure you have the help you'll need to handle all the inspection and testing duties. Notify your supervisor when the surfacing placement is about to begin and tell him that you'll need a scale person ticket writer, a ticket receiver, and a density inspector to work with you. The surfacing aggregate will be weighed either in the haul trucks on a truck scale or by a belt scale as it's discharged from the plant. Check to see that the scale certification is up to date. Look for a current sticker. Every six months or whenever the scales are moved, the contractor must get his scale certified and stamped. Division one of the specs contains additional scale requirements. Project layout is another preliminary concern. First, you should check the roadway cross sections and note the length of the job to see if the planned quantities of aggregate will be sufficient. The surveying will be done sometimes by the contractor's crew, sometimes by the department crew, and sometimes by you. Make sure that stakes and hubs to control the alignment and grade are set properly according to stationing or mile posts as required. On this project, hubs with turkey tails attached to their tops are set along the center line and shoulder lines to indicate the finished grade of the base course. Go over the plans carefully. Check the drainage adjustments in particular and review the miscellaneous details thoroughly. Yet another preliminary concern before the work begins is approval of the contractor's equipment on the project. The equipment to be used depends in part on whether the operation will involve the central plant mix method or the road mix method. Both are described in the specs, but the road mix method is the one we'll look at here. Be sure to inspect the equipment according to the specification requirements. It should be in good condition and be able to do the job properly. Look especially at the spreading equipment. During the job, you'll take both acceptance samples for field casting and assurance samples to send to the district lab according to the frequencies given in the construction manual. But before the work begins, you should notify the independent assurance samplers. After the work is underway, they'll come out to the project to obtain samples for the headquarters lab. More on sampling and testing later. There's one more preliminary concern to check the subgrade slope and condition. The subgrade must be approved prior to placing surfacing. Its surface must not deviate more than plus 500 foot from the grade established by the subgrade blue tops. You can check this conformance to grade in various ways, string line, rod and level, straight edge or swedes. As for condition, the subgrade surface should be smooth and compacted to density specifications. Look for bumps, depressions or soft areas. Any such defective areas should be repaired before surfacing placement begins. Be certain that no aggregate is placed on poor quality subgrade. Some subgrade problems such as pumping may not show up until loaded trucks drive over them. These may require more extensive repair efforts such as French drains or digouts and construction fabric. In any case, document all subgrade problems and inform your supervisor. The project engineer will determine the solutions and issue a change order to cover any needed work. Now let's look at your duties during production. First, the aggregate is weighed on a belt scale at the plant or in the haul trucks on commercial or contractor scales. The scale person ticket writer has to ensure accurate weighings of the loaded trucks. Periodically throughout the day, this person must check to see that the scale is balanced and returns to zero. The scale person also should determine at least once each day if the scale is operating within one half of 1% of the weighed load. The ticket receiver must collect the ticket from each driver. For safety, be sure the truck stopped completely for the ticket receiver to take and initial the tickets. In addition to the initials, the receiver should verify the time the load is received and the location. And also check the item numbers and quantity totals. The yield also must be checked frequently to avoid wasting material. By keeping track of the amounts of aggregate in the trucks and the distances over which they're spread, you can figure the yield easily. Be aware that the department observes only the legal load limits. So if there are any overages at the point of loading, the scale person should tell the contractor and give him the opportunity to offload the excess weight. If the contractor doesn't want to offload the excess weight, the ticket receiver should cross out the actual weights right in the legal limits and initial the changes. This project calls for placing a crushed surfacing base course, followed by a crushed surfacing top course, each with a different gradation of aggregate. So be sure the right material is placed for each course. You'll need to monitor the aggregate supply, making sure that the correct stockpiles of aggregate are being used and that they're sampled and tested according to the construction manual's frequencies. The aggregate for each layer of surfacing has to be hauled to the roadway in approved hauling equipment, such as bottom dump trucks, with either longitudinal or transverse spreading capability. You should know, however, that the combination of longitudinal and transverse spreading equipment is not permitted in the same section of a project as determined by the engineer. On this job, the contractor spots the placement of each truck load of aggregate on the road by placing a delineator post to mark the beginning of the spread. He does this by referring to the spread stakes, set at stations along the shoulder line. The truck driver starts dumping his load at the post, spreading the aggregate up to the end of the previous load placed. So the truck's haul, place, and partially spread the aggregate. But motor graders complete the spreading by working the aggregate back and forth across the roadway in several passes until it's evenly and uniformly placed. The spreading of aggregate on small areas of less than 2,000 square yards or on irregularly shaped areas may be done by other means approved by the engineer. Still, you need to ensure that the aggregate is spread with minimal segregation and to the correct line, grade, and depth of course. The depth placed for any course should be as shown in the plans and should not exceed the maximum depths given in the specs. For ballast, five-tenths of a foot. For gravel base, 7,500s of a foot. And for crust surfacing, 3,500s of a foot. These are the nominal depths of compacted material and are not to be exceeded without the engineer's approval. The greater operators control the width and depth of spread by blading to the hubs set along the center line and both shoulder lines. The turkey tails can be seen by the operators even when the hubs are slightly covered over during the spreading. As the aggregate is spread, visually check its overall gradation. Even though the gradation may be okay at the point of acceptance, the aggregate may become segregated during hauling, placing, or spreading. Segregation is indicated by concentrations of course or fine material as you see here. Problem may be corrected when the graders blade the material back and forth because of the mixing that occurs. But if the problem isn't corrected by the blading, the base course will end up being unstable. Traffic running over it will displace the loose aggregate and cause failure. So look out for segregation at all times. Also look for any foreign objects in the spread aggregate. Plant matter, pieces of wood, lumps of soil or clay, or other debris, are contaminants that will produce defective areas in the surfacing if not detected and removed. Water is applied as needed during surfacing placement to replace the moisture lost by evaporation. The water makes the aggregate easier to mix and spread, holds down the dust, and is necessary to achieve compaction. Now the compaction of the surfacing is accomplished by both the haul trucks being routed effectively over the roadway in the use of vibratory compactors and rollers. Water should continue to be applied as needed during compaction to keep the base moist so that adequate density can be obtained. The completed layer should have a smooth, tight, uniform surface, reasonably true to the line, grade, and cross-section shown in the plans. This project calls for a bituminous surface treatment Class A to be constructed on the crushed surfacing top course. So the completed surface is left in the fluffed up condition that will allow it to be penetrated by the prime coat of asphalt. You'll need to check the depth of the surfacing by digging holes in the completed courses and measuring down to the top of the previous course from a straight edge. Density testing must be conducted according to the frequencies in chapter nine of the construction manual. The testing will be done by the nuclear gauge for a Washington densometer. You'll have to monitor both the tests and the results. The density inspector, of course, should document them thoroughly. When areas of the surfacing fail density tests, you must notify the contractor and ensure that the problem areas are corrected and that retests are made before paving takes place. Throughout surfacing placement, maintain good communication with the plant inspector, the scale person, and the density inspector. Make sure that everyone is fully aware of individual duties, the scheduled work hours, and the necessary forms to complete. And never forget to communicate with the contractor too. Advise him immediately of unacceptable material, faulty equipment or work methods, and deficient areas of surfacing. Document the work thoroughly, neatly, and accurately by completing the inspector's daily report, depth check records, and daily compaction reports. One very important duty related to safety is traffic control. Be sure that the contractor follows an approved traffic control plan. The department supplies the signs, the contractor furnishes the other devices, including any flaggers. You need to be sure that flaggers are certified. Finally, your post-production responsibilities include compiling final quantities, mainly by checking the tickets and totalling the cubic yards or tons of aggregate placed. And that brings us to the end of this presentation on surfacing placement. High quality aggregate construction won't happen by itself. It requires the contractor's best efforts and your dedicated inspection of every facet of the job.